EEOC is first-step gatekeeper to pursuing an employer for discrimination, on age, gender, race, ADA-covered disability, nationality, investigation participant & some municipalities cover other protected classes.
But EEOC is only first step. It grants you right to sue, and reports to your employer that it, EEOC, has not dismissed your case and is allowing it to proceed to court, if you choose to file suit. Your employer may start to worry at this point. If your case is good, your employer/their legal counsel will know it and want to settle.
But the first step in all of this is go to an employment attorney and concisely share how you believe you have been discriminated against and what specific negative outcome has happened, whether termination, demotion, etc.
If they turn your case down, you pay nothing. If they take the case, it's a good sign, as lawyers want to take cases they can win and make money from.